1. Field of the Invention
The present invention relates to a stirring device for an automatic washer, and more particularly to a stirring device rotatably mounted in the interior of washing tub of an automatic washer and comprising stirring blades with an improved shape.
2. Description of the Related Art
Generally, in a stirring type automatic washer in which a stirring device or agitator is disposed within a washing tub and alternately rotated in normal and reverse directions, the washing power exerted to the materials of washing and the degree of entanglement of the materials of washing greatly depend upon the construction and shape of the stirring blades of the stirring device, the mounting position of the stirring device in the washing tub, and the rotation cycle of the stirring device.
As a conventional device applied to such a agitating type automatic washer, for example, there is a construction wherein a plurality of stirring blades are mounted on the upper surface of a circular base plate and extended outwardly and radially from the center of the base plate. There is also a construction wherein a rotating rod having a cylindrical or conical shape is vertically mounted on the center of the upper surface of circular base plate and provided with a plurality of stirring blades at the outer surface thereof. In this construction, stirring blades may be vertically extended from the rod and spaced uniformly from one another. Alternatively, a single stirring blade may be used, which helically extends throughout the length of the rotating rod and around the outer surface thereof.
In the former construction comprising a plurality of stirring blades radially protruded from the upper surface of circular base plate, the vertical flow of washing materials is smoothly carried out by virtue of the rolling of the washing materials generated by the function of stirring blades to wind the materials around the blades. However, this action of the stirring blades also causes the washing material to be entangled and thereby lumped, so that washing power is insufficiently transmitted to the inner part of the lump of materials of washing. Due to the entanglement of the washing materials, it is inconvenient to take up the materials from the washing tub after the washing is completed. In addition, there is a drawback that severe vibrations are generated during the dehydration operation.
On the other hand, in the latter construction comprising vertical stirring blades mounted on a rotating rod, the wash materials are wound around the rotating rod when the amount of the materials is large, so that a flow of the materials from the center portion toward the outer portion can not be smoothly carried out thus, the materials can not be uniformly washed. In the construction comprising a helical stirring blade disposed on the outer surface of a rotating rod, vertical and radial flows of the wash materials can be smoothly carried out. In this case, however it is hard to eliminate the problem that the wash materials are wound around the rotating rod. Since the wash materials rise very easily and rapidly, there is a disadvantage of reducing the stirring efficiency of the washing tub at the bottom portion effecting greatly the stirring power.
In addition to the above-mentioned stirring devices, many proposals have been made, all of which in various ways change the shape and construction of stirring blade in order to improve the washing power and eliminate the entanglement of the wash materials. However, they are all unable to provide an effect sufficient to improve the washing power and simultaneously eliminate the above-mentioned entanglement.